The invention relates to a liquid flow control apparatus, and particularly for use with an apparatus for adding a small amount of a first liquid (such as a medicant) per unit volume to a flow of a second liquid (such as a water supply for farm animals). A proven device for accurately adding desired amounts of medicant to the flow of water is shown in U.S. Pat. No. 3,084,712. This device includes a receptacle which is interiorly divided by a flexible membrane having first and second sides, with a first liquid--medicant--in contact with the second side of the membrane. An inlet conduit is operatively connected to the receptacle on the first side of the membrane, and an outlet conduit is operatively connected from the receptacle on a second side of the membrane. A pipe for containing the flow of water has a first part thereof operatively connected to the inlet conduit, and a second part thereof operatively connected to the outlet conduit. In order to provide for proper proportioning of the medicant into the flow of water, means are provided for producing limited flow and a differential pressure between the first and second pipe parts. Such means take the form of a disc having an orifice therein, the disc mounted at the junction between the first and second pipe parts. Flow conditions can be changed by stopping the flow of water, disassembling components of the apparatus, and replacing the disc with another disc having a differently sized orifice therein.
While the medicating apparatus as described in U.S. Pat. No. 3,084,712 works well, it is inconvenient and time consuming to stop the water flow, disassemble components of the apparatus, and the like in order to change the orifice size. According to the present invention, this problem is overcome by providing a mechanism that allows the orifice size to be changed quickly and easily. According to the invention, the orifice size may be changed without stopping the flow of the second liquid, or without disassembling any parts of the apparatus.
The flow control apparatus according to the invention comprises a block having first and second generally parallel faces, with the pipe first part extending generally perpendicular to the first face, and the pipe second part extending generally perpendicular to the block second face and generally in alignment with the pipe first part. An internal cavity of the block defines a guide, and the cavity is in fluid communication with the pipe first and second parts. A slide is received within the guide for slideable movement with respect thereto in a dimension generally parallel to said first and second block faces. Means defining a plurality of differently sized orifices in said slide are also provided, each orifice extending through the slide in a dimension generally parallel to the pipe first and second parts. The slide is mounted so that upon sliding movement thereof different orifices will come into alignment with the pipe first and second parts. Sealing means are associated with said block and slide to confine liquid flow therethrough from the pipe first part, through the orifice of the slide in alignment with the pipe parts, and out the pipe second part.
The block is preferably mounted directly to a top surface of the receptacle, and preferably the block is of a plastic material and is segmented, having an internal cavity, with the segments ultrasonically welded together. The sealing means preferably is provided by an O-ring associated with each of the block segments, and preferably detents are provided for holding the slide into each position wherein an orifice is in alignment with the pipe parts.
It is the primary object of the present invention to provide an apparatus for adding a small amount of a first liquid per unit volume to the flow of a second liquid, and allowing the pressure differential producing orifice size to be changed quickly and easily, and without disassembly of any apparatus components. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.